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<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
  <div class="the_div">
    <p>我是p标签</p>
    <h3>我是h3</h3>
    <h3>我是h3</h3>
    <h3>我是h3</h3>
    <a id="theA" href="#">我是一个a标签</a>
    <ul>
        <li>北京</li>
        <li>天津</li>
        <li>南京</li>
    </ul>
    <ol class="my_li">
        <li>大张</li>
        <li>大王</li>
        <li>大狗</li>
    </ol>
    <ul class="my_li">
        <li>小明</li>
        <li>小红</li>
        <li>小蓝</li>
    </ul>
</div>
<script>
  const h3 = document.querySelectorAll('.the_div h3')
  console.log(h3);
</script>
</body>
</html>